A Commentary, Critical, Practical, and Explanatory on the Old and New Testaments, by Robert Jamieson, A.R. Fausset and David Brown  at sacred-texts.com
deu 4:1AN EXHORTATION TO OBEDIENCE. (Deu 4:1-13)
hearken, O Israel, unto the statutes and unto the judgments, which I teach you--By statutes were meant all ordinances respecting religion and the rites of divine worship; and by judgments, all enactments relative to civil matters. The two embraced the whole law of God.
deu 4:2Ye shall not add unto the word which I command you--by the introduction of any heathen superstition or forms of worship different from those which I have appointed (Deu 12:32; Num 15:39; Mat 15:9).
neither shall ye diminish aught from it--by the neglect or omission of any of the observances, however trivial or irksome, which I have prescribed. The character and provisions of the ancient dispensation were adapted with divine wisdom to the instruction of that infant state of the church. But it was only a temporary economy; and although God here authorizes Moses to command that all its institutions should be honored with unfailing observance, this did not prevent Him from commissioning other prophets to alter or abrogate them when the end of that dispensation was attained.
deu 4:3Your eyes have seen what the Lord did because of Baal-peor . . . the Lord thy God hath destroyed them from among you--It appears that the pestilence and the sword of justice overtook only the guilty in that affair (Num 25:1-9) while the rest of the people were spared. The allusion to that recent and appalling judgment was seasonably made as a powerful dissuasive against idolatry, and the fact mentioned was calculated to make a deep impression on people who knew and felt the truth of it.
deu 4:5this is your wisdom and your understanding in the sight of the nations, which shall hear all these statutes--Moses predicted that the faithful observance of the laws given them would raise their national character for intelligence and wisdom. In point of fact it did do so; for although the heathen world generally ridiculed the Hebrews for what they considered a foolish and absurd exclusiveness, some of the most eminent philosophers expressed the highest admiration of the fundamental principle in the Jewish religion--the unity of God; and their legislators borrowed some laws from the constitution of the Hebrews.
deu 4:7what nation is there so great--Here he represents their privileges and their duty in such significant and comprehensive terms, as were peculiarly calculated to arrest their attention and engage their interest. The former, their national advantages, are described (Deu 4:7-8), and they were twofold: 1. God's readiness to hear and aid them at all times; and 2. the excellence of that religion in which they were instructed, set forth in the "statutes and judgments so righteous" which the law of Moses contained. Their duty corresponding to these pre-eminent advantages as a people, was also twofold: 1. their own faithful obedience to that law; and 2. their obligation to imbue the minds of the young and rising generation with similar sentiments of reverence and respect for it.
deu 4:10the day that thou stoodest before the Lord . . . in Horeb--The delivery of the law from Sinai was an era never to be forgotten in the history of Israel. Some of those whom Moses was addressing had been present, though very young; while the rest were federally represented by their parents, who in their name and for their interest entered into the national covenant.
deu 4:12ye heard the voice of the words, but saw no similitude--Although articulate sounds were heard emanating from the mount, no form or representation of the Divine Being who spoke was seen to indicate His nature or properties according to the notions of the heathen.
deu 4:15A PARTICULAR DISSUASIVE AGAINST IDOLATRY. (Deu. 4:14-40)
Take . . . good heed . . . for ye saw no manner of similitude--The extreme proneness of the Israelites to idolatry, from their position in the midst of surrounding nations already abandoned to its seductions, accounts for their attention being repeatedly drawn to the fact that God did not appear on Sinai in any visible form; and an earnest caution, founded on that remarkable circumstance, is given to beware, not only of making representations of false gods, but also any fancied representation of the true God.
deu 4:16Lest ye corrupt yourselves, and make you a graven image--The things are here specified of which God prohibited any image or representation to be made for the purposes of worship; and, from the variety of details entered into, an idea may be formed of the extensive prevalence of idolatry in that age. In whatever way idolatry originated, whether from an intention to worship the true God through those things which seemed to afford the strongest evidences of His power, or whether a divine principle was supposed to reside in the things themselves, there was scarcely an element or object of nature but was deified. This was particularly the case with the Canaanites and Egyptians, against whose superstitious practices the caution, no doubt, was chiefly directed. The former worshipped Baal and Astarte, the latter Osiris and Isis, under the figure of a male and a female. It was in Egypt that animal-worship most prevailed, for the natives of that country deified among beasts the ox, the heifer, the sheep, and the goat, the dog, the cat, and the ape; among birds, the ibis, the hawk, and the crane; among reptiles, the crocodile, the frog, and the beetle; among fishes, all the fish of the Nile; some of these, as Osiris and Isis, were worshipped over all Egypt, the others only in particular provinces. In addition they embraced the Zabian superstition, the adoration of the Egyptians, in common with that of many other people, extending to the whole starry host. The very circumstantial details here given of the Canaanitish and Egyptian idolatry were owing to the past and prospective familiarity of the Israelites with it in all these forms.
deu 4:20But the Lord hath taken you, and brought you forth out of the iron furnace--that is, furnace for smelting iron. A furnace of this kind is round, sometimes thirty feet deep, and requiring the highest intensity of heat. Such is the tremendous image chosen to represent the bondage and affliction of the Israelites [ROSENMULLER].
to be unto him a people of inheritance--His peculiar possession from age to age; and therefore for you to abandon His worship for that of idols, especially the gross and debasing system of idolatry that prevails among the Egyptians, would be the greatest folly--the blackest ingratitude.
deu 4:26I call heaven and earth to witness against you--This solemn form of adjuration has been common in special circumstances among all people. It is used here figuratively, or as in other parts of Scripture where inanimate objects are called up as witnesses (Deu 32:1; Isa 1:2).
deu 4:28there ye shall serve gods, the work of men's hands--The compulsory measures of their tyrannical conquerors would force them into idolatry, so that their choice would become their punishment.
deu 4:30in the latter days, if thou turn to the Lord thy God--either towards the destined close of their captivities, when they evinced a returning spirit of repentance and faith, or in the age of Messiah, which is commonly called "the latter days," and when the scattered tribes of Israel shall be converted to the Gospel of Christ. The occurrence of this auspicious event will be the most illustrious proof of the truth of the promise made in Deu 4:31.
deu 4:41Then Moses severed three cities on this side Jordan--(See on Jos 20:7).
deu 4:44this is the law which Moses set before the children of Israel--This is a preface to the rehearsal of the law, which, with the addition of various explanatory circumstances, the following chapters contain.
deu 4:46Beth-peor--that is, "house" or "temple of Peor." It is probable that a temple of this Moabite idol stood in full view of the Hebrew camp, while Moses was urging the exclusive claims of God to their worship, and this allusion would be very significant if it were the temple where so many of the Israelites had grievously offended.
deu 4:49The springs of Pisgah--more frequently, Ashdoth-pisgah (Deu 3:17; Jos 12:3; Jos 13:20), the roots or foot of the mountains east of the Jordan.